diff --git a/src/crypto/sha256/sha256.go b/src/crypto/sha256/sha256.go
index e1cccf65a6030..659531dc716f7 100644
--- a/src/crypto/sha256/sha256.go
+++ b/src/crypto/sha256/sha256.go
@@ -259,12 +259,12 @@ func Sum256(data []byte) [Size]byte {
 }
 
 // Sum224 returns the SHA224 checksum of the data.
-func Sum224(data []byte) (sum224 [Size224]byte) {
+func Sum224(data []byte) [Size224]byte {
 	var d digest
 	d.is224 = true
 	d.Reset()
 	d.Write(data)
 	sum := d.checkSum()
-	copy(sum224[:], sum[:Size224])
-	return
+	ap := (*[Size224]byte)(sum[:])
+	return *ap
 }
diff --git a/src/crypto/sha512/sha512.go b/src/crypto/sha512/sha512.go
index 9c143a2a28177..d5715558c0484 100644
--- a/src/crypto/sha512/sha512.go
+++ b/src/crypto/sha512/sha512.go
@@ -337,31 +337,31 @@ func Sum512(data []byte) [Size]byte {
 }
 
 // Sum384 returns the SHA384 checksum of the data.
-func Sum384(data []byte) (sum384 [Size384]byte) {
+func Sum384(data []byte) [Size384]byte {
 	d := digest{function: crypto.SHA384}
 	d.Reset()
 	d.Write(data)
 	sum := d.checkSum()
-	copy(sum384[:], sum[:Size384])
-	return
+	ap := (*[Size384]byte)(sum[:])
+	return *ap
 }
 
 // Sum512_224 returns the Sum512/224 checksum of the data.
-func Sum512_224(data []byte) (sum224 [Size224]byte) {
+func Sum512_224(data []byte) [Size224]byte {
 	d := digest{function: crypto.SHA512_224}
 	d.Reset()
 	d.Write(data)
 	sum := d.checkSum()
-	copy(sum224[:], sum[:Size224])
-	return
+	ap := (*[Size224]byte)(sum[:])
+	return *ap
 }
 
 // Sum512_256 returns the Sum512/256 checksum of the data.
-func Sum512_256(data []byte) (sum256 [Size256]byte) {
+func Sum512_256(data []byte) [Size256]byte {
 	d := digest{function: crypto.SHA512_256}
 	d.Reset()
 	d.Write(data)
 	sum := d.checkSum()
-	copy(sum256[:], sum[:Size256])
-	return
+	ap := (*[Size256]byte)(sum[:])
+	return *ap
 }